| 摘要 |
PROBLEM TO BE SOLVED: To improve the positioning accuracy of a head with respect to a disk by mounting two pairs of linear encoders at positions in separated horizintal surfaces on a carriage around an X axis, allowing the pair of offsets in the vertical direction of the encoders to decide the amount of the pitich of the carriage and eliminating the pitch while allowing a feedback circuit to drive a precise positioning device. SOLUTION: A tester 100 roughly positions a carriage 30 supporting a magnetic head 40 along front part rails 22, 24 with a stepping motor 32 and precisely positions it with a piezoelectric actuator 48. Encoders 12, 14 and 16, 18 measure linear displacements of the carriage 30 in first and seconf horizontal surfaces, The displacement in the horizontal direction of a magentic head 40 due to a pitch from an average displacement S2 is calculated based on average displacements S1, S2 which are measured respectively by the encoders 12, 14 and 16, 18 of the cartridge 30 with respect to a base 50 in the first and second horizontal surfaces and the cartridge 30 supporting the magnetic head 40 is made to be moved by using the feedback circuit.
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